Various coupling assemblies or plugs are known for coupling hydraulic or pneumatic conduits. In general, one form of plug to connect fluid coupling includes a female half having a longitudinal bore with a sealing ring and a lock ring mounted in the bore. A male half includes a nipple having a sealing surface for contact with the sealing ring to create a seal between the halves. The nipple generally includes a barb extending outwardly from its outer surface to create a shoulder against which the lock ring would be disposed to mechanically lock the two halves together.
It would be desirable if such fluid couplings could be provided with some manner of readily disconnecting the two halves so that the halves can be separated from each other. It would also be desirable if some form of wear indicator device could be included in the fluid coupling to indicate that substantial wear has resulted to the barb. It would further be desirable if such fluid coupling could include some structure to verify that the two halves are mechanically locked together. It would also be desirable if some structure could be provided to prevent relative rotation of one half with respect to the other when the halves are locked together and selectively permit relative rotation when it is desired to rotate one half without having to rotate the other half.